Can't seem to figure this one out. I have 4x HD 5970 in a HAF tower. Everything was working fine with old catalyst driver (have not updated since November 2013) and all 8 GPUs were recognized by the system.

Since latest oclhashcat required newer driver, I've uninstalled the old using the scrip from /usr/share/ati, reboot, installed catalyst 14.4, ran amdconfig --initial -f --adapter=all post installation. However now the system hangs during boot with a blank purple ish background.

If I do not execute amdconfig --initial -f --adapter=all system boots up fine but only 1 HD5970 is recognized.

I was able to figure it out. something weird about the 14.4 driver on my system. Ended up installing 14.6 beta which wanted me to install dh-modaliases execstack debhelper. now the system boots up fine and all 8 GPUs recognized by oclHC 1.21 and OS. just need to remember to use the --force switch